1. Field of the Invention
The invention relates to the art of collecting fluid samples, and more particularly to a fluid sampling device for obtaining precise volumes of fluid from a sealed container.
2. State of the Prior Art The ability to take precise volumes of sample fluid from a fluid supply, at a precise depth in the fluid supply, is important in many industries including oil exploration, lubricant jobbing, and in the chemical and food industries, in order to identify the qualities of the fluid, to measure the presence of contaminants and to the detect the fluid's physical properties.
U.S. Pat. No. 4,271,704 to Peters discloses a fluid sampler for taking a sample of a fluid in an oil well. A chamber is pressurized with a floating ball so the floating ball seals off the top end of a chamber. The device is lowered into an oil well. When the hydrostatic pressure in the oil well exceeds the pressure in the chamber, oil will fill the chamber, float the floating ball to the top, and again seal off the chamber so that no more oil enters the device. U.S. Pat. No. 4,271,704 to Davidowicz et al. discloses a fluid sampling device with a chamber with two balls--one floating and one non-floating. By pressurizing and depressurizing the float chamber, a precise sample of fluid can be obtained. U.S. Pat. No. 4,715,789 to Liegel et al. discloses a valve assembly for controlling hydraulic fluids. It utilizes balls and springs, but not floating balls.
While these devices may be suitable for obtaining samples from unsealed containers, they are not specifically adapted for quick attachment and detachment to sealed pressure containers, to ensure that the contents of the sealed pressure container is not contaminated with outside air and/or dust. There accordingly remains a need for a device for obtaining fluid samples from a sealed container.